Anti-spasmodic agents containing quaternary nitrogen

ABSTRACT

A new class of anti-spasmodic compounds having two branch chains and containing quaternary nitrogen is provided. The compounds have the general formula: ##STR1## wherein R 1  and R 2  are defined hereinbelow and m is an integer from 0 to 3.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to new pharmaceutical compounds having useful anti-spasmodic properties.

2. Description of the Prior Art

The purpose of an anti-spasmodic drug is to relieve spasms of the snooth muscles. Smooth muscles line most of the visceral organs. The peristalsis and muscular activity of the stomach, intestines, gall bladder, urinary bladder, lung, the uterus, and to a degree the heart are all largely controlled by smooth muscles. Smooth muscles are innervated by the autonomic nervous system. The autonomic nervous system consists of two antagonistic branches--the sympathetic branch and the parasympathetic branch. On all visceral organs except the heart the parasympathetic nerve impulses increase the irritability and tension of the smooth muscles; contrariwise, the sympathetic nerve impulses increase the tension and irritablilty of the muscles of the heart muscle and relax the smooth muscles of the other visceral organs.

A spasm in a smooth muscle may be due to one of two causes. Either the smooth muscle may be receiving exaggerated impulses from the autonomic nervous system which create violent contractions in the muscle, or the muscle may be intrinsically stimulated into a spasm (most likely from chemical changes in the surrounding tissue). A spasm due to exaggerated impulses from the parasympathetic branch of the autonomic nervous system may often be corrected by administering atropine (an active alkaloid of belladonna) which serves to break a connection between the parasympathetic nerve and the smooth muscle. This ability and effect of atropine is called a "neurotropic effect". A spasm intrinsic in the smooth muscle itself may often be corrected by papaverine (a derivative of opium which is classed as a narcotic). Papaverine has an ability to decrease intrinsically the contractility of smooth muscle; it has the ability to relax smooth muscles directly. This ability and effect of papaverine is called a "musculotropic effect".

In relieving spasms of smooth muscles generally, a musculotropic effect is acknowledged to be superior to a neurotropic effect. A neurotropic effect cannot relieve spasms intrinsic in the smooth muscle itself, while a musculotropic effect, by relaxing and decreasing the irritability and responsiveness of smooth muscle to stimulation from the autonomic nervous system, can help to relieve a smooth muscle spasm even when it is due to exaggerated impulses from the autonomic nervous system.

A clinical difficulty with atropine is that of undesirable side-reactions. Atropine when given in effective doses, serves to break or partly break all the parasympathetic nerve-smooth muscle connections throughout the body. Thus when atropine is given in sufficient dosage to relieve a spasm in a specific visceral organ, such as a gastric or intestinal spasm (the spasm caused by exaggerated nerve impulses from the parasympathetic nervous system) undesirable side-actions due to the breaking of the parasympathetic nerve-muscle connections elsewhere in the body may occur. The most easily recognized of these undesirable side reactions are dilation of the pupil and dryness of the mouth, caused by the breaking of the parasympathetic connections to the iris and the saliva producing mechanism respectively.

Atropine is acknowledged to have also a musculotropic effect, but its neurotropic effect is so strong that it cannot be given in greater than minute doses (1/60 to 1/40 grain) without encountering the undesirable side reactions. This dosage is too small to permit a significant musculotropic effect.

U.S. Pat. No. 2,390,555 discloses a class of compounds comprising di-N-substituted aminoethyl esters of diphenylthioacetic acid of the general formula (C₆ H₅)₂ --CH--COS--CH₂ CH₂ --R in which R represents a disubstituted amino radical of either the diethylamino group, the morpholino group or the piperidino group. This patent was based upon the discovery that the thio analogs of certain disubstituted acetic acid esters of aminoalcohols have desirable anti-spasmodic properties. These compounds have proven to be very effective and are widely used as anti-spasmodics without encountering the undesirable side reactions due to excessive neurotropic effect.

U.S. Pat. No. 4,432,997 discloses new uses, especially for the dilation of the smooth muscles of the upper urinary tract, of the compounds disclosed in U.S. Pat. No. 2,390,555.

In Compte Rendu de la Societe de Biologie, 140, pp 477-9, (1946) Dupre, Levy and Tchoubar disclose a series of compounds having the formula (C₆ H₅)(R)CHC(:O)SCH₂ CH₂ N(CH₂ CH₃)₂, where R is either a phenyl group, a propyl group, an isopropyl group, a butyl group or an isoamyl group. These compounds are all disclosed as being spasmolytic agents.

Compounds of the same general formula given above were prepared by Tchoubar and Letellier-Dupre in Bulletin de la Societe Chimique, pp792-4 (1947) wherein R was a phenyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isoamyl group or hydrogen.

In Farmakol. i. Toksikol., pp 10-17 (1956), Liberman discloses a class of compounds having the general formula (C₆ H₅)₂ CHCOSCH₂ CH₂ N--R₂, wherein both R's are the same and are selected from methyl, ethyl, propyl and butyl groups; and a class of compounds having the general formula (C₆ H₅)--CH(C₆ H₁₁)COSCH₂ CH₂ N--R₂, wherein both R's are the same and are selected from methyl, ethyl, propyl and butyl groups.

C. A. Buehler et al. in the Journal of Medicinal Chemistry, 6, pp 230-3 (1963) disclose physiologically active compounds of the general formula R(R')--C(OH)COS(CH₂)₂ NR"₂ wherein R and R' are aryl groups.

R. O. Clinton et al. in the Journal of the American Chemical Society, 68, pp 2076-7 (1946) synthesized a number of dialkyl aminoalkyl diarylthiolacetates including fluorene-9-carbothioic acid, S-[2-diethylaminoethyl]ester.

SUMMARY OF THE INVENTION

A new class of anti-spasmodic compounds is provided having the general formula: ##STR2## where R₁ is selected from the group consisting of: ##STR3## R₂ is a radical selected from the group consisting of ##STR4## and m is an integer from 0 to 3.

The present invention also comprises methods of administering the above-described compounds for, but not limited to, the treatment of patients suffering from pylorospasm in the upper and lower gastrointestinal tract, spasm associated with the gall bladder and common bile duct, as well as diarrhea, the irritable bowel syndrome, ureterospasm, bladder irritation, asthma and emphysema.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The anti-spasmodic compounds of the present invention are effective in a dosage range of from about 0.0025 to about 0.6 mg/kilogram of body weight per day. A preferred dosage is in the range of from about 0.065 to about 0.5 mg/kilogram of body weight per day. A still more preferred dosage range is from about 0.015 to about 0.25 mg/kilogram of body weight per day.

The anti-spasmodic compounds of the present invention may be combined with a pharmaceutically acceptable carrier and can be administered orally, typically in tablets of 400 mg active ingredient, total 1155 mg, or by intravenous injection, or by topical application.

Because the anti-spasmodic compounds of the present invention generally hydrolyze slowly in water, they are preferably not used as a serum or suspension unless used as a freshly prepared solution. It is possible, however, to encapsulate microspheres of these compounds in the form of a liquid suspension for administration to patients.

As specific examples of the compounds of the present invention, there can be mentioned: ##STR5##

The general reactions used in the synthesis of the anti-spasmodic compounds described in the present invention may involve a number of reaction mechanisms. In general, thioester tertiary amine hydrochlorides are prepared by heating 10 mol % of an acid chloride with 90 mol % of either the free base of the mercapto-alkyl tertiary amine or its hydrochloride in a suitable solvent until the reaction is complete and the Ellman reaction for free SH groups negative. Suitable solvents for this reaction are low boiling halocarbons such as dichloro methane or chloroform. Non-halocarbon solvents for this reaction include aceto nitrile. When the reaction is complete the solvent is removed, typically in a rotary evaporator under vacuum, and the residue either crystallizes spontaneously or is crystallized by cooling it in an ice bath, storing it in a refrigerator, cooling with dry ice/alcohol, or storing it in a freezer. The crystallized crude thioester-tertiary amine hydrochloride is recrystallized from either dichloromethane/pertroleum ether, ethyl acetate/hexane, ethyl acetate or acetone according to its solubility properties and the precipitated crystals collected on a vacuum filtrate apparatus and dried.

Alternatively, an alcohol can be converted to an alkyl halide and subsequently reacted with a thioglycol precursor: ##STR6##

The synthesis of the tertiary amine in the thiol ester analogues of Pro Banthine for example follows the above described method of preparation: ##STR7##

In this reaction, methobromide is used to add another methyl group to the existing 3° amine in the synthesis of a 4° amine or "quaternization". This reaction is represented as follows: ##STR8##

Another synthesis reaction for preparing the compound ##STR9##

Similar reaction mechanisms may be utilized in the synthesis of ##STR10##

The compounds of this invention are anti-muscarinic agents (cholinergic-muscarinic receptor antagonists) which inhibit the actions of acetylcholine on autonomic effectors innervated by postganglionic cholinergic nerves as well as on smooth muscle that lacks cholinergic innervation. Since a major component of parasympathetic control of smooth muscle occurs via muscarinic receptors, these compounds are effective as modifiers of smooth muscle activity.

Thiphenamil hydrochloride has been shown in decrease spasm of the gastrointestinal tract, biliary tract, ureter and uterus without producing characteristic atropinic side effects on salivary and sweat glands, GI glands, the eye or the cardiovascular system. This invention results in compounds which are as efficacious as thiphenamil hydrochloride, or more so, in relaxing various smooth muscle systems while at the same time demonstrating thiphenamil hdyrochloride's lack of associated side-effects. 

The following is claimed:
 1. A compound of the formula ##STR11## where R₁ is selected from the group consisting of ##STR12## and R₂ is selected from the group consisting of ##STR13## and m is an integer from 0 to
 3. 2. The compound as defined in claim 1, wherein R₁ is ##STR14##
 3. The compound as defined in claim 1, wherein R₁ is ##STR15##
 4. The compound as defined in claim 1, wherein R₁ is ##STR16##
 5. A method of treating a patient suffering smooth muscle spasm comprising administering to the patent an effective amount of the compound defined in claim
 1. 6. The method as defined in claim 5, wherein the compound is administered in a dosage of from about 0.0025 to about 0.6 mg/kg of body weight per day.
 7. The method as defined in claim 5, wherein the compound is administered in a dosage from about 0.065 to about 0.5 mg/kg of body weight per day.
 8. The method as defined in claim 5, wherein the compound is administered in a dosage of from about 0.015 to about 0.25 mg/kg of body weight per day.
 9. The method as defined in claim 5, wherein the compound is combined with a pharmaceutically acceptable carrier. 